I have an Arduino and BuckPuck I am currently building an LED array with.

As I was messing around with it I noticed that the Arduino and LCD screen powered up without it's own power source. This was because the BuckPuck's REF (+5V) pin was connected to the Arduino's Vcc, as is suggested in the BuckPuck datasheet.

So with that in mind, do I need a separate power source for the Arduino and related 5V logic circuits, or can the BuckPuck power it from the REF pin? It obviously can, but is it a good idea and can it source enough and be reliable enough as any other voltage regulator?